Electrofusion RTR Pipe Coupler for High-Pressure Joint Sealing
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Solution Overview
Problem
High-pressure reinforced thermosetting resin (RTR) pipe joint failures, particularly in high-temperature and high-pressure applications, are common due to improper installation and the limitations of existing joint designs, leading to leaks and reduced confidence in the material's performance.
Innovation Solution
The introduction of an electrofusion welding process using a coupler with resistive implant elements and thermoplastic tie layers, allowing for the fusion welding of RTR pipes to create a strong, sealed joint with a larger contact area, eliminating the need for secondary sealing mechanisms and simplifying the installation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive/bonded joints are used for RTR pipes, then lower pressure ratings can be achieved, but joint reliability deteriorates due to improper surface preparation and installation
Solution Approach 1:
The patent replaces mechanical/adhesive bonding systems with electrofusion welding. The coupler contains resistive implant elements that generate heat when electrical current is applied, melting the thermoplastic material to create a fusion bond. This substitutes the mechanical/adhesive system with an electro-thermal system that eliminates surface preparation requirements and provides more reliable joints.
Solution Approach 2:
The patent changes the physical state of the thermoplastic material from solid to molten and back to solid through controlled heating and cooling. The resistive elements heat the thermoplastic material above its melting point, allowing it to flow and bond the pipes, then cooling creates a strong fusion joint. This parameter change enables reliable bonding without adhesive application or surface preparation.
2Strength
If interference joints are used for high-pressure RTR pipes, then joint strength is improved, but device complexity increases due to threaded or key-lock mechanisms
Solution Approach 1:
The patent replaces complex mechanical interference joint mechanisms (threads, key-locks) with electrofusion welding. Instead of mechanical interlocking components, the system uses electrical current passed through resistive implants to melt and fuse thermoplastic material, creating a simplified yet strong joint without moving parts or complex geometries.
Solution Approach 2:
The patent uses a composite structure combining thermosetting resin pipes with thermoplastic material in the coupler. The thermoplastic material is embedded within or applied to the thermosetting pipe ends, creating a composite joint system that leverages the strength of thermosetting resin and the weldability of thermoplastic material.
3Ease of operation
If traditional joint designs are used, then installation process is simplified, but sealing reliability deteriorates due to improper installation and joint failures
Solution Approach 1:
The patent replaces mechanical sealing mechanisms (gaskets, O-rings, thread compounds) with electrofusion welding. The resistive heating system melts the thermoplastic material to create a monolithic fusion bond that inherently seals the joint, eliminating the need for separate sealing components and their associated installation complexities.
Solution Approach 2:
The electrofusion system is self-regulating through the resistive heating process. When electrical current is applied, the resistive implants automatically generate heat proportional to the current and resistance, melting the thermoplastic material without requiring external temperature control or monitoring. The process self-regulates until the material fuses and cools, creating a reliable seal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution significantly reduces joint failures, enhances sealing reliability, and allows for de-skilled installation, while providing improved joint strength and the ability to mitigate electrostatic discharge, thus increasing the confidence in RTR pipe technology for higher operating envelopes.
Implementation Method 1
the resistive elements are heated sufficiently to melt the thermoplastic material
Data Source
AI summary
A system for coupling pipes includes a first pipe having a tapered, spigot end; a second pipe having a tapered, spigot end; and a coupler having two tapered socket ends adapted to internally receive the respective tapered, spigot ends of the first pipe and the second pipe. The first pipe and the second pipe are made from a reinforced thermosetting resin (RTR). The coupler comprising a resistive element implanted therein and connected to electrodes extending to an exterior of the coupler. A thermoplastic material is disposed between an exterior of the first pipe and an interior of the coupler. A thermoplastic material is disposed between an exterior of the second pipe and the interior of the coupler. Upon application of electricity to the electrodes, the resistive elements are heated sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler. A method of coupling pipes includes disposing a thermoplastic material between an exterior of a first pipe and an interior of a coupler; disposing a thermoplastic material between an exterior of a second pipe and the interior of the coupler; inserting the first pipe and the second pipe into the coupler; and applying of electricity to electrodes of the coupler such that resistive elements of the coupler heat sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler.